I was reading up about Cibachromes, and they talk about getting Kodak Masking Film for making contrast masks. Can you still get this? or is there an alternative?

Daniel.

There are several alternatives that one may use. Any conventional pan film will work. I would opt for a slow speed film (25-125 ISO) since this gives more freedom in exposures.

I would not use an ortho film such as APHS in the case of masking a color material. The ortho emulsion will not work as well because it is not balanced nearly as well to the colors in the transparency.